The ntsb is now investigating this crash. And it's a reminder of what a hot air balloon trip is like. It's not exhilarating and romantic, at times can be dangerous. And Linzie Janis continuing our coverage this morning with that angle of the story. Reporter: It's been called man's first form of flight and one of the safest. The French invented hot air balloons in the late 1700s. Pilots say they can even be landed if they run out of fuel, the fuel that heats the air. But when one hits a power line, the result is almost always tragic. Hot air balloon rides are thrilling and beautiful. But not without risk. Oh, no. Reporter: Last year, a San Diego couple lifted off for their wedding. Only to come crashing down through a fence and into a nearby neighborhood. I got a little worried when we hit the fence. And I thought, if the fence doesn't stop us, we're going down this hill. Reporter: Former FAA inspector Dominick tomello, said the picturesque tours can be dangerous. What's the biggest risk in flying a balloon? Power lines, by far. Reporter: One of the most tragic hot air balloon crashes was in January 2012. A scenic flight in New Zealand, collided with a high-voltage power line while attempting to land. The fire caused the balloon to disintegrate, killing all 11 people onboard. And just over a year ago, former NFL wide receiver Donte Stallworth had a brush with death, leaving him and a friend badly burned when their south Florida balloon trip went terribly wrong. I began to become concerned when I was looking back behind me and I saw that we were getting really close to the power lines. And by the time I realized that we were going to hit the power line, it was too late. Reporter: There have been about half a dozen serious hot air balloon accidents in the last five years globally. The deadliest among them was last year in Egypt. That balloon caught fire killing 19 of 21 passengers onboard. 19 is the number that has been killed in U.S. Hot air balloon crashes since 2001. Have you ever been in one? I haven't. I never had a desire to go in one. I wasn't afraid to. Reporter: I was in one. It's an incredible experience. It's kind of floating. Yeah. It has risks. It does. Linzie, thank you.

This transcript has been automatically generated and may not be 100% accurate.

Mother's Day Hot Air Balloon Ride Turns Tragic

A hot air balloon ride turns deadly after flying into power lines.

Romantic Hot Air Balloon Ride Goes Terribly Wrong

Stephen Richardson had just proposed to his girlfriend when the balloon slammed into live power lines.

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